The subject invention generally relates to the measurement of temperatures within a body, and more particularly to a system of temperature measurement by monitoring the pressure fluctuations due to thermal vibrations in the body as a function of frequency.
There are many situations in medical diagnosis and treatment, industrial processing, geophysical exploration, and other fields where the temperature inside a material body is desirable to measure, but it is not practical to insert a probe beyond the surface of the body. In medical diagnosis, the usefulness of temperature measurement at the few places available for probe insertion is well established. In recent years, thermograms produced by infrared camera equipment and other surface temperature measurement have shown promise as a means of detecting breast cancer lesions. A technique which extends temperature measurement to all soft-tissue parts of the body offers promise as a powerful new diagnostic tool.
In medical therapy, a non-invasive temperature monitoring technique would be useful in almost any procedure involving heating or cooling of the soft tissues of the body. For example, hyperthermia has been found to be a promising technique, either alone or in combination with other modalities, for the treatment of cancer. However, its effectiveness is very sensitive to the temperature which is reached, becoming more effective as one approaches 45.degree. C., but tissue necrosis becomes a serious problem if the temperature goes above 45.degree. C. Therefore, a non-invasive method of monitoring temperature profiles is important if hyperthermia is to have wider potential.
In industrial processing, a suitable temperature distribution inside a large, hot body is often important during the heat treatment and cooling process. For example, the casting of large thicknesses of glass and other brittle materials is costly, partly because of a high failure rate which might be alleviated by a non-invasive temperature monitoring system. Data needed for geophysical exploration and monitoring would be more readily obtained if non-invasive accoustic-radiometry could provide temperature profiles as a function of depth for distances of several meters into surface rocks or into the region around a bore hole.